There is an increasing need for network and communication bandwidth. Optical networks have been developed to enable network operation at increased bandwidth and speed, as optical signals are capable of traveling farther than electrical signals at the data rates required by modern day networks.
Although data is transported optically in optical networks over optical fibers, the data is still processed primarily in the electrical domain in network devices such as data center switches and servers, optical network units (ONUs), optical network terminals (ONTs), optical line terminals (OLTs), and the like. This creates the requirement for electrical to optical conversion of data, which is an important purpose of optical transceivers or optical modules. For example, FIG. 1 shows an optoelectronic transceiver 10 that receives electrical signals from a host (e.g., through a port Rx [Host]), converts the received electrical signals to optical signals, and transmits the optical signals to a network (e.g., through a port Tx [Network]), and that receives optical signals from the network (e.g., through a port Rx [Network]), and that converts the received optical signals to electrical signals, and transmits the electrical signals to the host (e.g., through a port Tx [Host]). Thus, in networks, network devices that use devices such as the optoelectronic transceiver 10, data is processed in electrical circuits but transmitted over the network in the optical domain, allowing for longer transmission distances. As Integrated Circuits (ICs) continue to improve in their switching capacity, even the electrical Input/Output (I/O) pins or pads of the IC can become a limiting factor for the IC performance. Future generations of ICs are preparing to use optical I/O ports instead of electrical I/O ports to address this problem. These optical I/O ports will likely have small optical link budgets that may be capable of addressing only shorter distance network applications, thereby not servicing the full needs of the optical network.
One possible solution to this problem is a pluggable optoelectronic module that includes first and second optical-electrical-optical (OEO) converters. One OEO converter converts optical signals from the network to optical signals for the host, and the other OEO converter converts optical signals from the host to optical signals for the network. Each OEO converter includes a number of optical receivers configured to convert optical signals to electrical signals, electrical signal processing circuitry communicatively coupled to the optical receivers, and a number of optical transmitters configured to receive electrical signals from the signal processing circuitry and to convert the electrical signals to optical signals. This allows for conversion of a low-link-budget optical link to a high-link-budget optical link, permitting longer transmission distances that many network links require. However, the electrical signal processing circuitry in the inbound and outbound data transmission paths operates in the electrical domain, and thus increases the transceiver complexity and power consumption associated with requiring electrical circuitry in the OEO converter.
This “Discussion of the Background” section is provided for background information only. The statements in this “Discussion of the Background” are not an admission that the subject matter disclosed in this “Discussion of the Background” section constitutes prior art to the present disclosure, and no part of this “Discussion of the Background” section may be used as an admission that any part of this application, including this “Discussion of the Background” section, constitutes prior art to the present disclosure.